(CNN) — Daniel Inouye, the Medal of Honor-winning World War II veteran who represented Hawaii in the Senate for five decades, has died, his office announced Monday. He was 88.

He died of respiratory complications shortly after 5 p.m. at Walter Reed National Military Medical Center, with his wife and son at his side.

Inouye was hospitalized last week and had undergone procedures to regulate his oxygen intake.

He won his ninth consecutive term in 2010 and was the second longest-serving senator in the chamber’s history, trailing only Sen. Robert Byrd of West Virginia. Inouye was a senator for all but three of the Hawaii’s 53 years as a state and had served as its first House member before that.

He enlisted in the U.S. Army shortly after the attack on Pearl Harbor. In World War II, Inouye lost an arm charging machine gun nests in San Terenzo, Italy, earning him the Medal of Honor.

He served as chairman of the Senate Committee on Appropriations and the Senate Commerce Committee, and was the first chairman of the Senate Select Committee on Intelligence.

Inouye graduated from the University of Hawaii and the George Washington University School of Law.

Asked recently how he would want to be remembered, the senator said: “I represented the people of Hawaii and this nation honestly and to the best of my ability. I think I did OK,” according to his office.